Retrovirus- mediated gene transfer

- A retrovirus is a virus that carries its genetic material in the form of RNA rather than DNA.

- increase the probability of expression, gene transfer is mediated by means of a carrier or vector, generally a virus or a plasmid.
- Retroviruses are commonly used as vectors to transfer genetic material into the cell, taking advantage of their ability to infect host cells in this way.
Offspring derived from this method are chimeric, an organism consisting of tissues or parts of diverse genetic constitution.
- Transmission of the transgene is possible only if the retrovirus integrates into some of the germ cells.
- Providing that the genetic manipulation does not lead to abortion, the result is a first generation (F1) of animals that need to be tested for the expression of the transgene.
- Depending on the technique used, the F1 generation may result in chimeras. When the transgene has integrated into the germ cells, the so-called germ line chimeras are then inbred for 10 to 20 generations until homozygous transgenic animals are obtained and the transgene is present in every cell.
- At this stage embryos carrying the transgene can be frozen and stored for subsequent implantation